[Zope] DocumentLibrary or new product ?

[Frank Stephan]

Hi,

I need an application similar to DocumentLibrary.
But I have to make some modifications:

1. I want to assign user rights for a specific topic (folder)
2. The files should be stored externally and not in ZODB.
3. I want to specify, which document types are allowed in a topic (folder)

Is there a chance to modify DocumentLibrary to fit my needs or
would it be better (easier) to code a new product?

TIA
Frank